You don't have to like it, but facts don't stop existing because you don't like them.
https://en.wikipedia.org/wiki/Metrication#:~:text=In the 19th century, the,law was adopted in 1871).
Take a look at this chart. The last time a country switched over completely to the metric system was 2005, and it was a small island with nowhere near the infrastructure of the U.S. Prior to that was 1975. That's forty-six years ago. 70.5% of countries that are completely switched over to the metric system did so prior to 1950. There was just less infrastructure to switch over.
The reality is it's easy to sit back and say that we're stupid for not switching over to the metric system, but that's ignorant. There are lots of factors and nuances involved.
As I said earlier, the metric system is the more efficient system of paper (though not in every aspect), but it's a waste or resources to switch over. We can understand and use the imperial system just fine.